Spring loaded catalytic converter with externally mounted spring

ABSTRACT

In a catalytic converter having a casing with an inlet and outlet for exhaust gas flow and a peripheral catalyst element seat at one end, a monolithic catalyst element within the casing against the seat and a flow reversing baffle having a peripheral rim engaging the end of the catalyst opposite the seat, a load bearing member has a peripheral rim engaging the peripheral rim of the baffle and a central finger projecting outward through an opening in the casing into a ported retainer cup fixed to the outside of the casing; and a conical spring is compressed inside the cup with the large diameter end abutting the cup and the small diameter end engaging the finger to exert force through the load bearing member to hold the catalyst member firmly against the seat, the ported retainer cup allowing atmospheric air circulation over the spring for cooling.

Bray et al.

United States Patent 1 1 Dec.9,1975

Cole, Bloomfield Hills; James A. Haggart, Jr., Davison, all of Mich.

[73] Assignee:

[22] Filed:

General Motors Corporation,

Detroit, Mich.

Aug. 20, 1974 21 Appl. No.2 498,261

[52] US. Cl. 23/288 FC; 23/288 F [51] Int. Cl? B01J 8/00; F01N 3/15 [58]Field of Search..... 23/288 F, 288 FC; 138/108,

References Cited 1 UNITED STATES PATENTS Spackman 210/168 lnnes et a1.23/288 F UX Ridgway..... 23/288 FC ux Thomas 23/288 FC Innes 23/288 FHardis0n.... 23/288 FB X Lang et a1 23/288 FC UX Berger et a1 23/288 FVII/lil/I/II/I/III 3,801,289 4/1974 Wiley 23/288 FC 3,823,555 7/197423/288 FA UX 3,824,788 7/1974 Cole et a1 23/288 FC UX 3,838,977 10/1974Warren 23/288 F Primary'ExaminerBarry S. Richman Attorney, Agent, orFirm-Robert M. Sigler [57] ABSTRACT In a catalytic converter having acasing with an inlet and outlet for exhaust gas flow and a peripheralcatalyst element seat at one end, a monolithic catalystelement withinthe casing against the seat and a flow reversing baffle having aperipheral rim engaging the end of the catalyst opposite the seat, aload bearing member has a peripheral rim engaging the peripheral rim ofthe baffle and a central finger projecting outward through an opening inthe casing into a ported retainer cup fixed to the outside of thecasing; and a conical spring is compressed inside the cup with the largediameter end abutting the cup and the small diameter end engaging thefinger to exert force through the load bearing member to hold thecatalyst member firmly against the seat, the ported retainer cupallowing atmospheric air circulation over the spring for cooling.

1 Claim, 1 Drawing Figure VIIIIIIIIIII 15,

Dec. 9, 1975 SPRING LOADED CATALYTIC CONVERTER WITH EXTERNALLY MOUNTEDSPRING BACKGROUND OF THE INVENTION This invention relates to catalyticconverters for internal combustion engine exhaust systems andparticularly to such converters having monolithic catalyst elementswithin a casing. It is desirable to hold such monolithic catalystelements firmly in place within their casings to prevent chipping andbreakage of the element during shock or vibration. However, it isadvisable to plan for different rates of thermal expansion between theceramic based catalyst element and the metal casmg.

One method of holding the catalyst element firmly within the casingwhile allowing for different thermal expansion between the element andthe casing is to spring load the catalyst element within the casing witha spring stronger than any shock to which the converter is likely to besubjected. However, the high temperatures usually maintained in theoperation of such catalytic converters require special alloy springs tomaintain their force characteristics; and this adds to the cost of suchconverters.

SUMMARY OF THE INVENTION This invention provides for a spring loadedmonolithic catalytic converter with the spring maintained outside theconverter casing and exposed to atmospheric air for cooling. Thisinvention shows means whereby such a spring can exert a force on thecatalytic element within the casing and discloses a converter with ahigh strength spring of a design especially suited to maintaining acompact outer size for the converter. Further details and advantages ofthis invention will be apparent from the drawing and followingdescription of the preferred embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the FIGURE, acombustion engine exhaust system includes a catalytic converter 10, anexhaust passage 12 for carrying exhaust gases to catalytic converter andanother exhaust passage 14 for carrying exhaust gases from catalyticconverter 10. Exhaust gas passages 12 and 14 might be defined by anengine mounted exhaust manifold such as that partially shown at 16.

Catalytic converter 10 comprises a casing including a generallycylindrical shell 18 which is open at the axial end 20 nearest manifold16 and has a small axially central opening 22 at the other axial end 24.Retaining ring 26 is fixed around end 20 of shell 18 by welding orsimilar means.

The casing further comprises an annular end member 28 having aperipheral rim formed into a catalyst element seat 30 and pressed intoopen end 20 of shell 18. The radially inner portion 32 of annular endmember 28 fits around, and is sealingly fixed to, an inlet conduit 34which is aligned axially with respect to cylindrical shell 18 andextends axially toward the other end 24 of shell 18. Annular end member28 also includes one or more outlet openings 36 therethrough.

Catalytic converter 10 is mounted directly on manifold 16, with the openend of shell 18 sealed with an O- ring 38 on an outer circular mountingseat 40 and inlet conduit 34 sealed by an O-ring 42 to an inner mounting2 flange 44. With converter 10 thus mounted, inlet conduit 34 opens toexhaust passage 12; and outlet openings 36 open to exhaust passage 14. Aplurality of clamps 46, bolted to manifold 16 by bolts 48, engageretaining ring 26 and maintain converter 10 in place.

Within shell 18, a monolithic catalyst element 50 has one axial end 52abutting catalyst seat 30 and a central axial opening 54 through whichinlet conduit 34 extends. At the other end 56 of catalyst element 50, a7

flow reversing baffle 58 has a peripheral rim 60 which sealingly engagescatalyst element 50 at its outer diameter. A load bearing member 62 isdisposed within shell 18 just beyond baffle 58. Load bearing member 62has a peripheral rim 64 which bears against peripheral rim 60 of baffle58, a reinforcing disk 66 welded to the axial center thereof and afinger 68 fixed to the axial center of load bearing member 62 andreinforcing disk 66 and projecting outward through opening 22 in shell18.

A ported retaining cup 70 having ports 72 therein is welded to end 24 ofshell 18. Finger 68 thus projects into the volume enclosed by retainingcup 70. A sealing washer 74 surrounds finger 68 in opening 22 andprevents exhaust to the atmosphere of any exhaust gases that may haveescaped around baffle 58. Sealing washer 74 allows axial freedom ofmovement for finger 68 and thus for load bearing member 62.

A conical spring 76, within ported retaining cup 70, has a largediameter end 78 adjacent cup 70 and a small diameter end 80 engagingfinger 68 by means of an adapter 82. Spring 76 is compressed within cup70 and thus exerts an axial force through finger 68, load bearing member62 and peripheral rim 60 of baffle 58 to hold catalyst element 50 firmlyagainst catalyst element seat 30.

In operation, exhaust gases enter catalytic converter 10 from exhaustpassage 12 through inlet conduit 34 and fiow toward the other end ofconverter '10, where flow reversing baffle 58 forces them to fiow backthrough catalyst element 50 and outlet openings 36 to exhaust passage14. Flow reversing baffle 58 thus prevents contact between the hotexhaust gases and load bearing member 62.

Spring 76, being outside shell 18 in ported retaining cup 70, is removedfrom the hot area of the converter 10 and exposed to atmospheric aircirculating through ports 72 for cooling. The temperature of spring 76is thus reduced to the point where less expensive spring steel may beused. The conical design of spring 76 allows the coils to nest withineach other upon compression so that the axial length of the spring isreduced to the maximum extent for compactness of the catalytic converter10 and consequent maximum freedom of placement of catalytic converter 10within a crowded vehicle engine compartment.

The embodiment as described is only a preferred embodiment of thisinvention. Since equivalent embodiments will occur to those skilled inthe art, this invention should be limited only by the claims whichfollow.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A catalytic converter for an engine exhaust system comprising, incombination: a generally cylindrical housing having an axially centralinlet and an outlet at one end thereof for exhaust gas flow, aperipheral catalyst element seat at the one end thereof and an axiallycentral opening at the other end thereof; a generally cylindricalmonolithic catalyst element having one axial end positioned against thecatalyst element seat, another axial end and a central axial openingtherethrough extending between the axial ends and aligned with thehousing inlet for conducting exhaust gases from the one axial end to theother; a flow-reversing baffle having a circumferential rim in sealingcontact with the other axial end of the catalyst element, the bafflebeing effective to direct exhaust gas flow from the catalyst elementopening radially outward and back through the catalyst element to theoutlet; ported spring retaining means fixed to the other end of thehousing outside the housing opening; spring means positioned in thespring retaining means for cooling by atmospheric air; and aload-bearing member positioned between the flow-reversing baffle and theother end of the housing, the load-bearing member having a peripheralrim positioned against the peripheral rim of the flow-reversing baffleand a centrally positioned finger projecting out of the housing inslidable sealing engagement with the housing through the housing openinginto engagement with the spring means, whereby the force of the springmeans is transmitted through the peripheral rims of the load-bearingmember and flow-reversing baffle to the catalyst element to retain itfirmly against the catalyst element seat, the load-bearing member beingotherwise spaced from the flow-reversing baffle for minimum thermalcontact therewith, whereby the flow-reversing baffle protects theloadbearing member from the hot exhaust gases.

1. A CATALYTIC CONVETER FOR AN ENGINE EXHAUST SYSTEM COMPRISING, INCOMBINATION: A GENERALLY CYLINDRICAL HOUSING HAVING AN AXIALLY CENTRALINLET AND AN OUTLET AT ONE END THEREOF FOR EXHAUST GAS FLOW, APERIPHERAL CATALYST ELEMENT SEAT AT THE ONE END THEREOF AND AN AXIALLYCENTRAL OPENING AT THE OTHER END THEREOF:: A GENERALLY CYLINDRICALMONOLITHIC CATALYST ELEMENT HAVING ONE AXIAL END POSITIONED AGAINST THECATALYST ELEMENT SEAT, ANOTHER AXIAL END AND A CENTRAL AXIAL OPENINGTHERETHROUGH EXTENDING BETWEEN THE AXIAL ENDS AND ALIGNED WITH THEHOUSING INLET FOR CONDUCTING EXHAUST GASES FROM THE ONE AXIAL END TO THEOTHER; A FLOW-REVERSING BAFFLE HAVING A CIRCUMFERENTIAL RIM IN SEALINGCONTACT WITH THE OTHER AXIAL END OF THE CATALYST ELEMENT, THE BAFFLEBEING EFFECTIVE TO DIRECT EXHAUST GAS FLOW FROM THE CATALYST ELEMENTOPENING RADICALLY OUTWARD AND BACK THROUGH THE CATALYST ELEMENT TO THEOUTLET; PORTED SPRING RETAINING MEANS FIXED TO THE OTHER END OF THEHOUSING OUTSIDE THE HOUSING OPENING; SPRING MEANS POSITIONED IN THESPRING RETAINING MEANS FOR COOLING BY ATMOSPHERIC AIR; AND ALOAD-BEARING MEMBER POSITIONED BETWEEN THE FLOW-REVERSING BAFFLE AND THEOTHER END OF THE HOUSING, THE LOAD-BEARING MEMBER HAVING A PERIPHERALRIM POSITIONED AGAINST THE PERIPHERAL RIM OF THE FLOW-REVERSING BAFFLEAND A CENTRALLY POSITIONED FINGER PROJECTING OUT OF THE HOUSING INSLIDABLE SEALING ENGAGEMENT WITH THE HOUSING THROUGH THE HOUSING OPENINGINTO ENGAGEMENT WITH THE SPRING MEANS, WHEREBY THE FORCE OF THE SPRINGMEANS IS TRANSMITTED THROUGH THE PERIPHERAL RIMS OF THE LOAD-BEARINGMEMBER AND FLOW-REVERSING BAFFLE TO THE CATALYST ELEMENT TO RETAIN ITFIRMLY AGAINST THE CATALYST ELEMENT SEAT, THE LOAD-BEARING MEMBER BEINGOTHERWISE SPACED FROM THE FLOW-REVERSING BAFFLE FOR MINIMUM THERMALCONTACT THEREWITH, WHEREBY THE FLOW-REVERSING BAFFLE PROTECTS THELOAD-BEARING MEMBER FROM THE HOT-EXHAUST GASES.